Trombone.



D. A. McDONALD.

TROMBONE. APPLICATION FILED FEB. 19, I917.

Patentd Apr. 16, 1918.

UNITED STATES PATENT OFFICE.

DAVID A. MCDONALD, OF CHICAGO, ILLINOIS, ASSIGNOR TO LYON & HEALY, OFCHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TROMBONE.

Specification of Letters Patent.

Patented Apr. 16, 1918.

7 '0 all whom it may concern:

Be it known that I, DAVID A. MCDONALD, a citizen of the United States ofAmerica, and resident of Chicago, Cook county, Illinois, have invented acertain new and useful Improvement in Trombones, of which the followingis a specification.

My invention relates to an improvement in .trombones, and. particularlyto an improved construction in the slide, whereby this slide may bereadily moved to its various playing positions. The feature of myinvention consists in providing a novel construction by which the readymovement of this slide is greatly facilitated in that the area offrictional engagement between the telescoping members is greatlydecreased without, at the same time, unnecessarily decreasing the lengthof the bearing surface. In this manner, I am enabled to provide aneflicient and firm bearing between the two parts of the slide and yet sodecrease the area of frictional engagement as to render the slide moreeasy of operation.

These and other features and objects of my invention will be morereadily understood by having reference to the accompanying drawings, inwhich I have illustrated one form of trombone embodying the features ofmy invention.

Figure 1 is a side elevation of a trombone constructed in accordancewith my invention.

Fig. 2 is an enlarged detail view tion of the slide bearing.

Fig. 3 is a sectional view taken on the line 33 of Fig. 2.

Fig. 4; is a detail view of one arm of the slide bearing, showing amodified construction.

As illustrated, I have shown a trombone of well known type comprisingthe bell 5, mouthpiece 6 between which is located the usual tone slideconsisting of the U-member 7 which telescopes over the two parallel arms8 and 9.- This U slide is provided with the usual cross piece 10 wherebyit can be moved in and out to its various playing positions.

In previous constructions it has been found that, owing to the largearea of surface engagement between the U slide 7 and the arms 8 and 9,there is a tendency for the slide to stick and that therefore it isdifficult to quickly and accurately move the slide to of a porthedesired position while playing the instrument. In order to avoid suchobjectionable features, and to provide a slide which not only is firmlymounted on the arms 8 and 9 but also one which can be readily slid inand out over such arms I provide a novel construction, clearly shown inFig. 2. This consists of a bearing ring or stocking 11 which is mountedon the end of each of the arms 8 and 9, which bearing ring iscomparatively short but forms a close air tight connection between thetwo members. having this bearing member constructed comparatively shortin this manner, I avoid unnecessary friction between the telescopingmembers. However, if such a short bearing member were used alone itwould not be sufficient to hold the U slide firmly on the arm that is,the U slide would tend to wabble and not be firmly held when the slidewas drawn out to its lower positions. In such a con struction, the slidenot being held in proper alinement, there is a tendency for this slideto jam when being moved quickly from one position to another, and inthis way interferes with the free movement of the slide. In order toobviate this objectionable feature I provide a plurality of bearingstrips 12 which are secured to the surface of the arms 8 and 9 adjacentto the bearing rings. These strips are of sutlicient length to provide afirm bearing between the telescoping members and are placedcircumferential y around the tubular arms with a space between the same.In this manner I have provided an elongated bearing surface with aminimum area of surface engagement between the telescopin parts and thusobtain this increased length of engagement without materially increasingthe friction between the parts.

In Fig. 4: I have shown a slightly modified construction in whichinstead of having the bearing ring and bearing strips formed separatelyI provide a single bearing memher which is mounted on the end of thearms 8 and 9, this member consisting of a metallic collar 13 to whichare secured the elongated arms 14, intern'iediate spaces 15 beingprovided between each pair of arms. In this construction, as in theprevious construction, it will be noticed that I have provided a maximumlength of bearing surface whereby the U slide is firmly supported on thetubular arms without unduly increasing the total surface engagementbetween the members and thus Without unduly increasing the frictionbetween the telescoping parts.

It will thus be seen that I have devised a very efficient structure andone in which the U-slide is firmly and efficiently supported on thetubular arms of the instrument and in such a manner that the frictionalengagement between the moving parts is reduced. It will be noticed thatin the construction shown in Fig. 2 there is a small space between theinner end of these bearing strips and the bearing rings 11. This is ofutility in cleaning the instrument from dust or other foreign particles.

While I have illustrated and described certain specific constructionsfor carrying out the features of my invention, it will be understoodthat other forms may suggest them- Copies of this patent may be obtainedfor five cents each, by addressing the selves to those skilled in theart without departing from the spirit and scope of my invention.

What I claim as my invention is:

l. A trombone comprising a pair of parallel tubular arms, a U-slide intelescoping engagement with said arms, and a plurality of bearing stripssecured to said tubular arm and forming a bearing between said arms andsaid slide.

2. A trombone comprisin a pair of parallel tubular arms, a U-sli e intelescoping engagement with said arms, and a bearing ring and aplurality of elongated bearing strips on each of said arms for forming abearing between said arm and said U slide.

Signed by me at Chicago, Illinois, this 14 day of February, 1917.

DAVID A. MCDONALD.

Commissioner of Patents,

Washington, D. C.

